Hey Don,

I am a new ham, but have an interest in ARDF. I would be interested in helping but as I said I am very new to all of this stuff.

Let me know if there is a way I can help.

73,

~gd

Gary Dunn

KC3PLJ

Baltimore, MD

kc3plj@...

On Dec 6, 2020, at 2:18 PM, Don, W9EBK <donw9ebk@...> wrote:

If you would like to get involved in designing and building some 80 meter CW transmitters, I have an interesting project. I’ve been involved in Amateur Radio Direction Finding (ARDF) for many years. ARDF is the on-foot athletic competition type of radio direction finding that is internationally sanctioned under a very specific set of rules. I’m a member of the ARRL’s ARDF rules subcommittee and am involved with their other ARDF subcommittees. Lack of affordable and readily available equipment has been identified as a leading obstacle to growing the sport of ARDF in the United States. I’m proposing this project as a personal project, not sanctioned by the ARRL or any specific ham radio club.

   A company in China has brought out an affordable 80 meter ARDF receiver. While not great, it’s good enough to get beginners started. But, affordable 80 meter transmitters that fit specific ARDF requirements are needed. The Chinese ARDF transmitters aren’t readily available and lack important features. European transmitters are expensive and have features that don’t match up with FCC regulations.

   Now for the tough part of the transmitter’s RF design. The antennas used in competition are a vertical wire 8 to 12 feet long supported by a fishing pole, with no counterpoise other than a ground rod. No ground plane wires  are allowed because the competitors would trip on them or pull them loose. This means the transmitter is working into a load of 8 to 10 ohms at best. An antenna tuner would work to correct this but the transmitters need to be able to be built with an enclosure, battery and micro-controller for $50 or less. Conventional variable capacitors would eat up a lot of that budget and tuning them would complicate setting to transmitters. 

   If you’ve read this far, Thank You. I will be happy to answer specific questions off the reflector but here’s a short list of requirements. The transmitters need to put out around 2 to 5 watts of CW near 3.579 MHz, but with a few twists. ARDF competitions use 2 frequencies. 5 transmitters (Foxes) cycle on/off on one frequency while the Finish Line beacon on an adjacent frequency operates continuously. 2 frequencies programmable via DDS or crystal controlled with easily switchable crystals for something like 3.579 MHz and 3.585 MHz are needed. The Foxes cycle On for 1 minute sending a certain code sequence with the callsign at the end of the minute and off for 4 minutes. Timing must be just right so transmitter 1 identifies and goes off just as transmitter 2 comes on, etc. Timing needs to hold to within 1 second for several hours of operation. It’s best if the transmitters can be placed in the woods while turned off and have them all come on automatically at a certain time. This should be easy to accomplish with an Arduino or PIC as long as the callsign can be changed easily, as the transmitters will likely be passed around from club to club.

   

   If you are interested in tackling this project please contact me.

donw9ebk@...

Thanks,

Don, W9EBK

From: John Fitzer <jfitzer1053@...>
Date: December 3, 2020 at 2:57:43 PM CST
To: main+owner@4SQRP.groups.io
Subject: Fwd: Issue with Hilltoppers 30 kit

I am forwarding this to the group to alert anyone who may be building the Hilltoppers 30. Please see below for two issues I encountered while building the kit. This in no way is a criticism of the kit or the team members. This is a quality kit with quality components. It should provide excellent service once built. My only. Goal is to help others so that they will be successful in building this fine qrp radio. Please see my comments below. I have. already notified Jim Pruitt so that he can check any unshipped kits.

Thanks and 73s.    W3BNO.

Begin forwarded message:

From: John Fitzer <jfitzer1053@...>
Date: December 3, 2020 at 2:38:16 PM CST
To: John Fitzer <jfitzer1053@...>
Subject: Fwd: Issue with Hilltoppers 30 kit

Begin forwarded message:

From: John Fitzer <jfitzer1053@...>
Date: December 3, 2020 at 2:36:14 PM CST
To: John Fitzer <jfitzer1053@...>
Subject: Fwd: Issue with Hilltoppers 30 kit

Begin forwarded message:

From: John Fitzer <jfitzer1053@...>
Date: December 2, 2020 at 4:13:44 PM CST
To: Jim Pruitt <jpruitt67@...>
Subject: Issue with Hilltoppers 30 kit

Jim I am assembling the Hilltoppers 30 kit and found a rather serious issue. The parts list denotes C2 as a .0022 (2200) pf capacitor. This is found in the band pack and is installed in group 6. The schematic shows a 220 pf cap and this is the correct value required to resonate the 4.7 micro Henry choke at 10.1 MHZ when connected in series with the 68 pf capacitor. My band pack contained a cap marked 222 (2200) pf in addition the parts lists C2 as marked 223 which would be (22000) pf. This is not an issue for me as I stock a good assortment of components from my days as a service tech. I just pulled one from my stock and kept on rolling. I only bring this to your attention so that you can correct the issue before you ship more kits. If someone builds this kit and the receiver has low gain they should probably confirm C2 is marked 221 and not 222. In addition R22, a 1K resistor was not marked as denoted in the manual. It's listed as conventional marked ( brown black red ) but it is marked with 4 bands ( brown black black brown ). Again for me this was not a problem but for a less experienced builder this could be an issue. If you think this could help someone please feel free to share.
Thanks and 73s

Good afternoon group.

I pleased to announce that we have the Ozark Patrol

Receiver kits back in stock and ready to ship.

We have a new kitter, Ted Mead and would be more than happy to ship you one in time for Christmas!

I hope you all are doing well during these trying time.

72

Johnny AC0BQ